Understanding Energy and Energy Policy

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Understanding Energy and Energy Policy

Zed Books Ltd

BASIC ENERGY AND POLICY CONCEPTS

When asked to think about energy, most people imagine a light going on in a house or driving a car. Certainly both of these activities require energy. But where does that energy come from? What source(s) was it derived from? How was it transported to the consumer? How does our energy usage affect the world around us? These are all important questions that require some knowledge about energy systems and sources to answer. As citizens, we have a responsibility to be able to rationally discuss energy-related topics. This chapter will provide an overview of terminology and concepts that will help our discussions of energy in the rest of the book.

Sustainable energy systems

Before we dive into energy-related terminology, let us take a look at where we, as a species, should be heading in terms of energy systems. We need more sustainable energy systems. 'Sustainability' – to borrow Thiele's working definition, which draws on science and ethics – 'satisfies meeting current needs without sacrificing future well-being through the balanced pursuit of ecological health, economic welfare, social empowerment, and cultural creativity' (2013: 4–5). We currently get most of our energy by mining solar energy captured eons ago by photosynthesis and stored as coal, oil, and natural gas in rock formations. It will take millions of years to produce new resources of this type, although we will not run out of oil or natural gas anytime soon, as we discuss in the chapter on fossil fuels. The carbon stored in these 'fossil' fuels is being released into the atmosphere, which is driving climate change. Climate change in turn will increasingly disrupt human activities, requiring us to expend more and more energy and resources just to maintain our current lifestyle. It would be preferable, and cheaper in the long run, to reduce carbon emissions gradually over the next several decades. The various ways that this reduction might be accomplished will be a main focus of the policy analysis of this text.

As an example of a sustainable energy system let us consider the Amazon rainforest. The rainforest is fueled entirely by solar power, sunlight absorbed by plants. This occurs at a fairly low total efficiency of around 1 percent, but encompasses a vast surface area. The concept of low efficiency but ubiquitous solar energy capture is a lesson for humanity and an idea we will return to in the chapter on solar power. Solar energy captured by plants is converted to sugars and other biomolecules, which are, in turn, food for the teeming animal biodiversity of the rainforest. Dead animals and plant matter fall to the floor of the forest, where bacteria and fungi rapidly break them down, releasing nutrients needed for new plant growth, beginning the cycle anew.

The solar energy first absorbed by plants is lost from the rainforest system as waste heat of metabolism at every energy transaction – for example, when an insect eats a plant and digests its tissues or when a bird eats that same insect. Nearly every usable bit of energy is extracted and nutrients are recycled in the rainforest; almost nothing stays in the soil. This is a truly sustainable system, and barring major climate change or being cut down by humans, it can continue to run indefinitely. As an aside, this is also why clearing the rainforest for agriculture requires so much additional energy input once the forest is cleared. Considerable amounts of manmade fertilizer, the making of which is an energy-intensive process, are required to make the land suitable for modern agriculture. This lack of nutrients stored in the soil also explains the use of slash-and-burn agriculture by the native peoples of the Amazon, and by those who have colonized the Amazon basin. Burning plants rapidly concentrates nutrients in ash that then improves the soil. However, this is a very inefficient process, and most nutrients are lost as escaping gases during burning. As a result, after a year or two, the soil is depleted, at which point the people move to another patch of forest.

Compare the Amazon rainforest to human systems. Many of our heating, cooling, and manufacturing systems are woefully inefficient when compared to natural systems. Large amounts of waste material are generated at every level of our society; much of this material ends up in landfills, where it sits taking up space, representing yet more wasted energy. Natural systems have had eons to evolve to their current states. We cannot wait so long, nor do we need to. We have the advantage of being able to change much more rapidly than natural systems can. Going forward, the societies or countries with the most sustainable energy systems are the ones most likely to endure. We have incentive to improve.

Let us start our discussion of energy with some basics of how we describe the movement of energy.

Thermodynamics Thermodynamics is classically defined as the study of heat flow. Thermodynamics led to improvements in the steam and internal combustion engines that helped to drive the Industrial Revolution forward. Today we generally think of thermodynamics in the wider context of energy flow, not just heat. Thermodynamics places constraints on what energy systems can and cannot do.

First Rule of Thermodynamics: Energy can neither be created nor destroyed; it can only be converted from one form into another There is a set amount of energy in the universe and you cannot make more. You cannot generate energy, for instance, you can only harness or convert energy that already exists. You can generate electricity, but this requires extracting energy from something else to cause a flow of current, which is electricity. Another way to state this law is that there are no free lunches. Energy must be extracted from a source, usually with consequences such as destruction or alteration of the energy source. There are a number of ways to state the first law, but the above version is among the most straightforward.

Second Rule of Thermodynamics: An isolated system, if not already in its state of thermodynamic equilibrium, spontaneously evolves towards it In thermodynamic equilibrium, there is no energy flow between parts of the system, because all parts of the system have exactly the same amount of energy. This rule also means that disorder tends to increase until all parts of the system are equally disordered. This rule makes more sense if we think of it in conjunction with the third rule.

Third Rule of Thermodynamics: The entropy of a perfect crystal at absolute zero is exactly equal to zero The third law also speaks to disorder, stating the only condition under which there is no disorder, implying that for other systems there must be disorder. The second and third laws together invoke the concept of entropy, which is variously described as 'disorder' or 'energy not available to do work.' According to the second law, disorder, or entropy, almost always increases in any energy transformation. This has practical applications; no energy transformation is 100 percent efficient; energy will always be lost to increase entropy. Often this lost energy is in the form of waste heat, which is diffuse energy that is difficult or impossible to capture to do useful work. So the more times you try to convert energy from one form into another, the less useful energy you have remaining.

An example of the utility of basic thermodynamics is the gas modifier scam. When automobile gas prices go up there is often an explosion of ads on the internet for gas modification systems that supposedly increase your gas mileage by 10, 20, 30 percent, or more. Often these systems also claim to never need replacing or recharging. Such claims should arouse considerable suspicion from a thermodynamic perspective. While it is possible to try to squeeze more energy out of gas combustion in an automobile engine, and carmakers have been trying to improve efficiency with limited success in various ways for decades, these systems invariably claim to modify the fuel. Consider carefully, though; if you are really modifying the fuel, then this is an energy transformation and entropy should have to increase. Furthermore the extra energy you get out of the fuel has to come from somewhere. Where is it coming from? Not the gas modifier, because that supposedly never needs replacing or recharging. Yet if it is adding energy to the system the gas modifier should get used up. Such claims fall under the umbrella of perpetual motion machines, machines that claim to need no input of energy to do work. Such machines are thermodynamically impossible.

Another way to state the three rules of thermodynamics is the poker analogy:

1st Rule: You cannot win. (You cannot take home more energy than you started with.)

2nd Rule: You cannot break even. (Entropy always increases, so you can only minimize your losses.)

3rd Rule: You have to play the game. (Entropy is positive for any temperature above absolute zero, so you lose energy whether you play or not.)

The poker analogy is pretty depressing and it makes one wonder how life is possible if you can never win in the energy game. If it keeps you from wasting money in casinos, then it is a good thing; a truism in both gambling and thermodynamics is that the house, entropy, always wins in the end. However, thermodynamics mainly talks about closed systems, where all the energy stays in a box and there is no net exchange with the outside environment. While this assumption may seem artificial, it is more applicable than you might think. Many human-engineered systems are essentially closed in a thermodynamic sense, thus the theory's utility.

Just by existing you are performing energy transformations and increasing entropy. In fact living organisms are sometimes referred to as entropy engines. We extract energy from the environment, giving off waste heat to entropy and using the rest of the captured energy to create order in our structured bodies. Evolution shapes living systems over time to be more and more efficient through competition, which results, for instance, in the rainforest example above. Human-made systems are not subject to natural evolution, but they are subject to market forces, where real markets are allowed to exist, and by public policy. We need to increase the efficiency of our human-made systems; this is the holy grail of engineered system sustainability, maximum thermodynamic efficiency. Increases in efficiency are likely to be as important as switching to truly sustainable energy sources to create a sustainable society.

The Earth itself is not a closed system. Energy from sunlight and heat from the radioactive decay of naturally occurring radioactive elements in the Earth's crust warm the Earth, and energy leaves as infrared, or heat, radiation to space. In fact it is a lowering of this output end of Earth's energy balance sheet that is behind global warming; more energy stays on Earth instead of being radiated away. As mentioned above, systems designed by humans are distinctly unnatural and we are just beginning to realize the full range of unintended consequences that we have unleashed on the Earth by changing the amount of heat that the Earth can radiate away to space by pumping greenhouse gases (GHGs) such as CO into the atmosphere. The Earth will find a new thermodynamic balance; we humans, along with myriad other species, will likely not be able to live as we currently do in the climatic conditions of Earth's new equilibrium.

Types of energy There are different types of energy. A few concepts that will help our understanding of energy are: kinetic and potential energy, and energy density. Kinetic energy is the energy of moving objects and is described by the equation:

F= ½M * V2

where F is the force the object can apply on striking another body, M is the mass of the body, which is equal to its weight on the Earth's surface (but weight is a product of gravity and will be different in space or on other planets), and V is the velocity of the object – that is, the speed at which it is traveling. Notice that the V term is squared, so velocity is much more important than mass. This is what makes a bullet so damaging. A bullet does not weigh much, but it is traveling at a high rate of speed, which, when squared, equals a large amount of energy released on impact. This is also what makes wind energy work. Air does not weigh much, but it can still carry a reasonable amount of energy when it starts to move.

Kinetic energy is not often directly applicable to energy systems; the exceptions are wind and hydropower. The kinetic energy of the wind can be converted into electricity or used directly to run equipment, such as an old-fashioned wind-powered grindstone for milling grains. Likewise hydropower harnesses the force of moving water.

What about water in a reservoir? Certainly it can be used to do work, but only once it is sent moving downhill under the force of gravity. How about before it starts to move? When the water is still in the reservoir it is said to have potential energy, it can be made to do work, but is not currently being used. Most energy systems rely on potential energy in one form or another. The water in the reservoir example is pretty easy to understand, but what about gasoline? It too has potential energy, but that extractable energy is locked in its very molecular structure, stored as chemical bonding patterns. When gasoline reacts with oxygen in a flame, the carbon compounds of gasoline are joined with oxygen from the air to create CO and energy is released. It is the portability of compounds storing chemical potential energy that underlies much of modern life and is the one reason human societies have become dependent on fossil fuels.

Energy density An additional reason that human societies use so much oil and gas, both fossil fuels, is because of their high energy densities. Energy density is usually defined as the amount of energy stored per unit of volume; however, some people also use it to mean energy per unit of mass. This ambiguity in the definition is unfortunate. The density of a fluid has a single definition, mass per unit volume – no ambiguity there. Unfortunately you will see energy density used to mean measured as either mass or volume. For some compounds this makes little difference. Gasoline, a liquid, has a high energy density whether you measure it in volume (liters or gallons) or mass (kilograms or pounds).

For gases such as methane or hydrogen, however, it matters a lot whether you are talking about mass or volume. For instance, hydrogen is a very good transportation fuel from a mass standpoint, assuming it is a liquid, which for hydrogen is quite an assumption because it takes tremendous pressure or very low temperature to liquefy hydrogen. Hydrogen is a very bad transportation fuel from a volume standpoint, assuming it is in its normal gaseous state, which occupies a large volume. So energy density is a useful term, but we must remember to compare apples to apples and make sure that the way the term is defined for a particular comparison is consistent.

Humankind's dependence on fossil fuels makes sense from an energy density perspective. Fossil fuels have a very high energy density. While it may have been possible to develop our current standard of living without relying on the remarkable energy density of fossil fuels, development would have proceeded at a much slower pace. The thorniest technological and regulatory hurdles ahead involve weaning humanity off our addiction to the high energy density of fossil fuels. We are not likely to find alternatives to fossil fuels that have as favorable an energy density; this is partly why advances in efficiency are so vital. We will need to learn to do more with less energy input.

Electricity generation In the developed world the most ubiquitous form of energy is electric current. Electricity is useful for some of the same reasons that gasoline is useful as a transportation fuel. Electricity can be moved long distances relatively easily and it can power a wide variety of devices. However, electric current is not just found or mined, it must be made. The term 'capacity factor' is used to measure how much electricity can be produced by a particular generating source. The capacity factor is the total theoretical generating capacity, often called 'nameplate' capacity, divided by the amount of time the system is actually generating electricity, basically the percentage of time a generating station is running at full power. For instance, most nuclear stations can achieve a 90 percent capacity factor, whereas wind turbines tend to be between about 25–40 percent of full capacity because the wind is not always blowing.

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Excerpted from Understanding Energy and Energy Policy by Timothy F. Braun, Lisa M. Glidden. Copyright © 2014 Timothy F. Braun and Lisa M. Glidden. Excerpted by permission of Zed Books Ltd.
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